Application of clonal culture techniques to the direct isolation and culture of cells from normal autopsy specimens and from patients with benign hypertrophy or carcinoma of the prostate has yielded over 40 cell lines of which 31 are preserved in liquid nitrogen. It is proposed to (1) Develop improved media and culture conditions for prostatic epithelial cells (2) Develop criteria for identification of cultured cells, and (3) Study hormonal binding, growth dependence, and response of cultured prostatic cell lines.